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Hessian fly takes big bite off NE Texas wheat crop

In early April, Northeast Texas wheat farmers were looking at what most described as potentially one of the best crops they’d ever seen.

They dodged a bullet from two cold snaps during Easter and the following weekend. Disease pressure was almost non-existent. Stalks were heading and filling with grain.

Growers hesitantly estimated upwards of 60 bushels per acre, a welcome prospect following back-to-back disaster years. And higher wheat prices promised a profitable harvest.

Then the second barrel was unloaded — a bullet they couldn’t evade.

Examining crop progress at mid-April, many growers noticed uneven growth and began looking for disease symptoms. They found none.

But, “We were looking at the wrong end of the plant,” says Robert Charles, Honey Grove, Texas, farmer.

When growers, consultants, and Extension specialists looked a bit lower, they discovered heavy infestations of Hessian fly, a tiny insect that deposits eggs on young wheat tillers.

Eggs hatch and the small maggots eat their way into and up wheat stalks, robbing the plant of nutrients and weakening it so it’s vulnerable to lodging. Potential losses can range from 25 percent to a train wreck.

Once the larvae get into the stalk, growers have no control options.

Charles expects to cut most of his wheat for hay. “We have identified infestation in 100 percent of our fields,” he says.

Texas Extension Integrated Pest Management Specialist Jim Swart, who works out of Texas A&M-Commerce, walked a field with Grayson County grower Jack Norman.

Slicing the thin blade of his Case Texas Toothpick pocketknife into wheat stalks in a heavily-infested field, he found Hessian fly pupae in nearly every stalk he cut. Some nodes contained as many as 15 dormant pupae, as well as active maggots (larvae).

Norman has identified the fly in about 75 percent of his wheat. Projected yield loss in individual fields ranges from 25 percent to 75 percent.

“The fly infestation is not uniform across the region,” Swart says. “The Leonard area, for example, has excellent yield prospects and few flies. Where fly populations are lower, I still expect farmers to harvest bumper crops — grain fill this year appears to be superb.”

Swart estimates Norman could lose half the potential crop across his entire infested acreage.

“Many growers will still make decent wheat yields because yield potential was so good,” Swart says. But the bin-buster many anticipated will not happen.

The fly has infested thousands of acres of wheat in the Northern Blacklands and into the Rolling Plains. Economic losses will be staggering in those fields.

“We’ve found Hessian fly infestations in about everything we’ve looked at,” says Danny Smith, Dorchester Grain Company, Dorchester, Texas. He estimates three-fourths or more of the crop in his area has been affected.

Swart says infestations appear worse in fields planted between October 5 and October 15; late fall rains likely triggered dormant flies to emerge and they found young wheat to infest.

“If we had received rain in late August or early September, we’d have been better off,” he says. Emerging that early would have put the flies in fields before wheat was available and a good portion of that generation would have died out.

Some native grasses also serve as hosts, however.

Norman planted almost all of his wheat during that vulnerable window.

“I haven’t found Hessian fly in later-planted wheat,” Swart says.

“We plant when we have moisture,” Norman says. “If we wait too long, the soil gets wet and we can’t get back in.”

General recommendations for managing Hessian fly include delaying planting until after frost. But in some years, Northeast Texas may not get cold weather until December — and that’s too late.

“We want our wheat out by late November at the latest,” Swart says.

Growers say this is the first time they’ve seen Hessian fly in this area in 20 years or more.

“I saw it for the first time in 1978,” Norman says, “and I hadn’t seen it again until this year.”

He says the 1978 experience convinced wheat producers to “change the way we farmed. We were planting mostly hard wheat, and we switched to soft varieties that showed resistance. We also did some deep plowing.”

Growers have relied on variety resistance to manage the pest, but have found heavy infestations this year in varieties that had shown significant resistance before.

“We’re not certain of the race,” Swart says. He and Extension Entomologist Allen Knutson have collected specimens from several areas and sent them in for race determination. He also says resistance may have broken down because of the large numbers of pests.

“Each female Hessian fly lays from 50 to 200 eggs,” he says. And, depending on weather conditions, the fly may cycle through four generations a year — two in the fall and two in the spring.

Swart says a mild February may have allowed flies to emerge, lay eggs, and produce an extra spring generation.

“We had no freeze days in February,” he says. Mild winter weather also may explain presence of larvae in upper nodes of wheat stalks. He says the larvae look for tender young growth and don’t fare well on wheat that has hardened off.

Some dormant pupae remain dormant to protect future generations.

Brothers Bruce and Rick Shipman, also of Honey Grove, a Fannin County farming community, know they have Hessian fly damage.

“We just don’t know how much,” Bruce says. “Some fields are worse than others.”

The pests came at a bad time. “In 2006, we baled a wheat crop, we baled a soybean crop, and we had to sell off cattle,” Rick says. “Cattle have continued to go up and now we can’t afford to sell any more because we need to rebuild our herd.”

He says 2005 was also a bad crop year.

Bruce says they planted most of this year’s wheat crop during that vulnerable October 5 through October 15 period. “We started a little earlier than usual in 2006.”

So did Charles. “I’ve pushed seeding rate down and planting date up,” he says. That early start gives the wheat a jump and produces more tillers. “I get more tillers with fewer seed; it’s more economical.”

He’s considering delaying planting next year, and he’s also considering tillage.

“We’ve moved away from tillage and are working in minimum-till production,” he says.

The Shipmans say summer deep tillage could be helpful. “But with $2.50 per gallon farm fuel, it’s not likely,” Bruce says.

Craig Moody, with Helena Chemical Company at Honey Grove, says this wheat crop has been expensive thus far. “Fertilizer costs are up, as well as fuel.”

Swart says many growers, reacting to good crop prospects and high wheat prices, added extra protection for the crop. “A lot of farmers applied fungicides,” he says.

“Farmers had already invested most expenses into this crop when they discovered the Hessian fly,” Moody says. “They had spent all production costs except harvest expenses.”

Many will lose most of that. Charles says he’ll decide soon whether to take the crop to grain or cut it for hay. “My insurance agent says to cut it and leave swaths to test later for yield.”

He’d like an earlier judgment to allow him to plant another crop.

“Insurance will not pay expenses,” says Bruce Shipman. “It’s not beneficial unless we’re wiped out. We need coverage on a field-by-field basis.”

Swart says growers have few options besides later planting to protect themselves from a repeat next year.

“We may go for years and never see Hessian fly,” he says, “but we’ll go into fall this year with huge numbers surviving.”

He plans to put in test plots next fall to examine potential for seed treatments.

Rick Shipman expects to sell a lot of this crop as hay. “People are looking for hay,” he says.

Charles says hay will sell for as much as $80 a ton for big round bales. That’s something — but small consolation to farmers who expected to take advantage of a bumper grain crop and high prices.

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